Can you paint in high humidity? What you need to know

If you’re planning a painting project and you’re concerned about humidity levels while you paint, you’ve come to the right place. Since paint needs to dry properly to have a beautiful and smooth result, moisture in the air is certainly an issue. So, can you paint in high humidity? While the answer to that question is yes, we’re going to discuss some of the concerns and tips for dealing with humidity and painting indoors or outdoors.

Red roller brush black paint on white wall
StockSnap/Pixabay

How does humidity affect your paint job?

Moisture in the air means that there’s moisture on the surface you’re about to paint. A damp surface is not ideal for painting, and you will find that your overall result doesn’t look as great as you’d hoped. Let’s dig into the specifics of how high humidity negatively impacts your paint job.

Moisture

When you’re dealing with high humidity, surfaces tend to dry slowly. When you’re painting indoors, for example, you always want to wash your walls before slapping down a coat of paint, so high humidity could slow down the drying process. If your walls are damp when you start to paint, this could lead to mold growing between the wall and the paint. The mold will eventually grow through the layer of paint, and you will need to clean the area and paint again.

Drying

For most paint types, for a coat to dry, the water in the paint needs to evaporate more quickly than the solvents. In high humidity, the water struggles to evaporate, making for a gunky, gel-like layer of paint. Eventually, when the humidity level falls, you’ll find that this type of consistency will dry with a wavy texture since it has not been set properly, and you won’t be satisfied with the poor result.

Impact on wood

As you may know, moisture on wood causes it to swell. If you’re painting wood when there’s a lot of moisture in the air, the wood could start to swell a bit after you’ve put on a coat of paint. This swelling could cause cracks or chips in your coat of paint which will eventually lead to the surface needing to be repainted.

Blue paintbrush against light wood fence
artursfoto/Pixabay

Tips for painting in high humidity

The perfect humidity level for painting, particularly outdoors, is between 40 and 50 percent relative humidity. Some moisture in the air is a good thing when you’re painting since you don’t want the paint to dry too fast and start to crack or peel. While painting in humidity levels above 50 percent is possible, you have to take some additional precautions to ensure a smooth and clean result. However, painting in humidity levels over 85 percent is highly discouraged since the paint will have such a difficult time drying.

Thoroughly dry surface before painting

If you’re painting indoors after you’ve washed your walls, be sure to wipe them thoroughly with a dry cloth to soak up any excess water. Then, set up some oscillating fans or even industrial blowers in the room for up to several hours to rid the walls of any residual moisture. It’s also a good idea to run a dehumidifier in the room for several hours before painting.

Paint at the right time of day

Particularly if your painting outdoors, the time of day plays an important role in your paint job’s success. As you approach mid-day, temperatures rise, and humidity falls, so begin painting during the early morning hours. That way, your paint will begin drying as humidity is getting lower. As the day goes on into the late afternoon, humidity levels increase as the temperature lowers, and you run the risk of condensation building up on your newly applied coat of paint. It’s best to stop painting as the day gets later.

Follow the sun

You don’t want to have freshly applied paint in direct sunlight since the paint will dry too quickly and not adhere properly, but the sun does help with warming surfaces and reducing moisture. When you’re starting your outdoor painting job, plan to begin with the surfaces that have been previously sitting in the sun but are now moving into the shade. These areas will be warmed and less moist but will not be in the sunlight as they dry.

Paint in thin layers

This one may be obvious, but thin layers dry more quickly, so if you’re facing highly humid conditions that will slow down the drying process, this is one way you can combat it. In the spirit of full disclosure, painting thin layers will require additional coats, but you’ll be more pleased with the outcome overall.

In a perfect world, you would only be painting when the humidity levels are ideal. However, since that’s not always the case, you may find yourself needing to paint when humidity is high. That doesn’t mean your paint job needs to suffer—painting at the proper time, taking the right precautions, and using the right products will go a long way in combating the moisture in the air so that you can enjoy a properly dried, even, and beautiful coat of paint.

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